Field of the Invention
The present invention relates to a sound insulation structure for a garment, a garment comprising a sound insulation structure and a method of manufacturing a sound insulation structure.
Background Art
Noise is generally perceived as a discomfort in everyday life, in particular in urban areas. Besides direct damages, especially to the eardrums and to the auditory nerve, noise may also cause mental stress, in particular if suffered for a longer duration. Furthermore, noise may be distracting and prevent people from relaxing or concentrating on intellectual tasks. This is especially a problem for people doing fitness sports as a means for compensating for professional stress. For example, joggers often seek to enjoy tranquility or listen to music via earphones, both of which may be hindered by an excessive urban noise level. Another example is an athlete in a noisy sports hall who wants to prepare mentally for a trial, a match, or a competition.
As a counter measure, noise-cancelling headphones are known in the art. Such headphones record the ambient noise with a microphone and emit a phase-inverted sound signal such that the original ambient sound and the phase-inverted sound signal annihilate at the wearer's ear.
However, noise-cancelling headphones are complex and expensive due to additional costs in the manufacturing of the noise-cancelling technology. Furthermore, noise-cancelling headphones need a battery which must be replaced or recharged. Finally, noise-cancelling headphones, which are often bulky and rather heavy, may not be suitable for sports activities.
CN203194611U describes a sound insulation garment capable of reducing damage of noise on the human body. The sound insulation garment comprises a garment body provided with a sound insulation component therein, and the sound insulation component is a sound insulation lining which is fixedly or removably connected with the garment body. When the garment body includes a cap, the sound insulation lining is arranged in both the garment body and the cap body.
However, such a sound insulation garment has limitations and may not be able to reduce the noise to an acceptable level. This is especially true for garments having a hood or cap. A hood or cap may act like a funnel which focuses ambient noise entering from the front onto a wearer's ear due to the almost semi-spherical shape of the hood. At the same time, noise may penetrate the hood or cap and from there may reach the wearer's ear without attenuation. The situation may even be worse because the cavity formed between the wearer's head and the surrounding hood or cap may act like a resonator and may amplify certain frequencies causing an opposite and adverse effect.